What equipment are you currently working on?

nullspace · « **Reply #140 on:** 12 Dec 2009, 01:34 am »

The bass certainly keeps up. Part of the reason for choosing the Kappa-12A is that they have no need for dampening from the amp -- the book value for qts is .27. Then, I can use the series attenuation needed without worrying about loose, flabby bass. Nothing new here, obviously, just vamping off the Nelson Pass whitepaper on transconductance amps w/ low-Q drivers.

I would've liked to use 15" drivers, but I couldn't fit four of them on a baffle and keep the mid- and treble- at a reasonable height.

John

JoshK · « **Reply #141 on:** 12 Dec 2009, 01:47 am »

So far, to date, I've heard two open baffle + hi eff implementations and they were both so-so. It very well could have had to do with the implementation, but they were a little slow sounding in the bass and like they were being held back; clean though and not boxy. The first was high Qts bass drivers, the second, I don't know. That is why I asked.

nullspace · « **Reply #142 on:** 12 Dec 2009, 02:39 am »

Sure. They do integrate quite well with the mids, and they are definitely more taut than the OB15 I have. But, that could also be because that the Eminence are a bit more rolled-off than the AE drivers, lending to the sense of lean-ness in the bass.

nullspace · « **Reply #143 on:** 12 Dec 2009, 07:46 pm »

Hey Josh,

I had another listen today, with the intent of fleshing out what you were talking about. I EQ'd up the low end via Foobar so that the freq. response would be a bit bass-heavy, then listened to some Beck ('Guero' and 'Sea Change'). Certainly the bass overwhelmed the small room I sit in, but it was still very tight and transitioned nicely to the mids. I don't want to say 'seamlessly' because that word gets thrown around too easily, but the integration is definitely one of the high points. Without the EQ, the bass was really excellent, if a bit light.

Now if only the response didn't drop-off a cliff under 45hz or so. I'm a little suprised by how much I miss that last octave, especially considering that the OB15 only covered down to 30hz. I could get one of those GR-Research servo subs, but with two huge (they're 36"Wx39"H btw) panels should I really have to? A task for another day.

Regards,
John

JoshK · « **Reply #144 on:** 12 Dec 2009, 07:59 pm »

Thanks John. I like to say I try to keep an open mind.

A couple years ago, I was sure this was the direction I wanted to go (OB + HE) but I changed my mind due to concerns that it wouldn't work well in my room, where the best listening setup is on the long wall and sitting only 9-10 ft back. I think there wouldn't be enough distance from the back wall in this position. If I did it the other way, it would likely work ideal but that is an awkward living room setup and I have to compromise with the lady.

So I change my direction some. In this time, I did get to hear two such setups and wasn't really overwhelmed as much as I thought I would be, so I was trying to see if it was those setups or the format. I am not trying to change your opinion at all.

Its unforunate just how long the wave lengths get at LF. It really makes for huge OBs or big HE bass boxes. No way to cheat the physics.

nullspace · « **Reply #145 on:** 12 Dec 2009, 08:17 pm »

Quote from: JoshK on 12 Dec 2009, 07:59 pm

I am not trying to change your opinion at all.

I didn't think that you were; I'm hoping just to be able to throw out another data point.

At times, I find myself thinking some of the same things, as much as I like open baffles and find aspects of them wonderful, there are some quite substantial tradeoffs. I spent the time I was walking the dog this afternoon wondering about Gary Pimm-style cardiod speakers...

By the way, how are your amps breaking in?

John

BobM · « **Reply #146 on:** 13 Dec 2009, 03:24 pm »

Currently burning in a pair of Russian .1uF Teflon caps (those big suka's) to use in my soon to be built Hagerman Piccolo step-up head amp. Parts are on the way from Mouser and Digikey. The only upgrades I'm making to it are using Vishay resistors, these teflon caps, and adding some extra capacitance to the battery power supply section (which usually helps to increase dynamics in my experience).

mgalusha · « **Reply #147 on:** 13 Dec 2009, 05:58 pm »

Working on hacking the I2S signal out of a m2tech hiFace to feed my 1st gen buffalo dac but with the 32bit ESS9018 chip. The bits are mostly done, still have to assemble and test it all and hope it works.

JoshK · « **Reply #148 on:** 15 Dec 2009, 02:44 pm »

Besides finishing up (pun) my bass bins, I have been working on a pair of amp chassis for Pass/First Watt clones. I bought a quad of Conrad heatsinks way back when in a diyA group buy. I have been collecting Peter Daniel boards (same size from board to board = reuseable setup).

I intend to build the power supply and probably an Aleph J clone first. Then I can experiment with the others pretty easily by swapping the boards (hopefully).

I got a chance to practice tapping last night. So far so good. I used the 1/2" thick faceplate's holes as a template to ensure my taps were perpendicular.

Tips I learned regarding tapping:
#1) use lubricant. It makes it a lot easier and helps you ensure you are staying aligned, as you can just feel it much better. (I bought aluminum lubricant, but I'm told alcohol works just as well).
#2) in blind holes use a bottoming type tap. Standard taps don't get the threads deep enough.
#3) some sort of guide template helps you stay straight.
#4) the spiral fluted taps are really slick (I bought mine on enco.com). They push the chards up and out as you tap.

jules · « **Reply #149 on:** 2 Jan 2010, 11:51 pm »

A useful trick I've discovered for using taps:

If you've got a drill press, insert the tap in the drill chuck, use the press to apply light pressure and manually wind the tap in to the point where resistance suggests you need to stop [err yes, a presumption here

]. After that, release the tap from the chuck while holding the press down. At this point the tap is far enough in to establish that it will stay perpendicular and in addition, the "press" start eliminates the uncertain feel you normally get. I've just done 30 or 40 taps into aluminium this way and it's much easier.

I used kerosene as a lubricant. It's ok and wouldn't evaporate quite as readily as alcohol.

Jules

Berndt · « **Reply #150 on:** 3 Jan 2010, 03:26 am »

As a machinist I would like to suggest wd40 for an aluminum taping fluid. Available and fairly harmless.
I would also suggest utilizing form taps which do not cut a chip, rather they form the material into it's thread shape.
You can make taping jigs out of a pc of 2x4 or plexy, just drill a clearance hole.
I use a cordless drill on slow to power tap, but would suggest this only on sizes over 1/4".
I can see that I would be more careful if an edm tap burner wasn't sitting at work.
If anyone is DIY'ing in the bay area and needs machinist help drop me a pm.

sts9fan · « **Reply #151 on:** 3 Jan 2010, 04:55 am »

I had a hell of a time with my first go at tapping. I do tend to go too fast with everything so I did snap a few taps. My Zv9 does have a broken tap in it. I used wd40 as a lube. The guide idea is a great one.

nullspace · « **Reply #152 on:** 3 Jan 2010, 05:04 pm »

Quote from: Berndt on 3 Jan 2010, 03:26 am

As a machinist...
If anyone is DIY'ing in the bay area and needs machinist help drop me a pm.

A machinist, you say? I'm in need of some Eimac HR1 grid/anode connectors, and they are unobtanium on the open market -- over the past three or four years I've gathered precisely two. So, I'm starting to look at getting them made. The jpg below is of the HR2, which is physically very similar. The HR1 is 11/16" long, 1/2" diameter, with a .052" diameter hole running the length. Would these be doable? Any idea what material would be best? Copper is appealing, but I suppose it would need to be plated and I don't have any idea how difficult that would be.

Regards,
John

ebag4 · « **Reply #153 on:** 3 Jan 2010, 06:03 pm »

I had forgotten about this circle or I would have posted here earlier. I recently finished a pair of GR Research N3s for my sister, this is what I posted in the GR circle:

"I bought the N3 kit fom Danny shortly after they became available. I worked on them throughout the year off and on, recently when I finally had a decent block of time I worked to finish them. These are for my sister to replace her worn out B**e 301s. I haven't had much time to listen but what I have heard so far is very good, although it is evident some break-in is required (they have only been playing for a couple of hours). Playing some AC DC at decent volumes has already started to improve the bass response. There are more similarities than differences to the sound of my OBs built with the MTM section of Danny's OB5. Anyway, without further adieu, here they are! BTW, Any attempted similarities to the asthetic of Jim Salk's Song Towers is purely intentional! Sorry Jim, please remember that imitation is the sincerest form of flattery.

"

Sorry guys, I didn't take any pics during the build, there was nothing really unique, different or significant to document. I am pretty happy with the way they turned out, my sister is very happy with them.

Best,
Ed

JoshK · « **Reply #154 on:** 3 Jan 2010, 11:37 pm »

Quote from: nullspace on 3 Jan 2010, 05:04 pm

A machinist, you say? I'm in need of some Eimac HR1 grid/anode connectors, and they are unobtanium on the open market -- over the past three or four years I've gathered precisely two. So, I'm starting to look at getting them made.

Another option is http://www.emachineshop.com/

nullspace · « **Reply #155 on:** 4 Jan 2010, 12:46 am »

Thanks for that Josh. Have you ever used them?

John

JoshK · « **Reply #156 on:** 4 Jan 2010, 02:38 am »

No, I just saw that suggestion on a diy forum recently. Can't remember where.

jeffdavison · « **Reply #157 on:** 4 Jan 2010, 09:40 pm »

Emachineshop.com
They supply the software and you do the drawings and submit them online. You get to choose the materials and the software gives you quotes before you commit. The are not inexpensive for one or two of a part as most of the costs involve setup. But when you get over 5 pieces, the cost per part becomes reasonable.

I've used them to make some parts for my Schroeder clone tonearm.
here's some links to my gallery where I have some pics:

http://www.audiocircle.com/index.php?action=gallery;area=browse;album=2506
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=2296

JD

nullspace · « **Reply #158 on:** 4 Jan 2010, 10:33 pm »

Thanks for the feedback Jeff. It goes without saying your tonearm is a ringing endorsement...

John

Scott F. · « **Reply #159 on:** 5 Jan 2010, 02:39 am »

Hey Jeff,

Nice job on the arm. Question, where did you get the arm lift? Is it a current manufacture or did you harvest it from a donor table?